Lithium Ion Conductor Crystallinity Control for Solid-State Batteries
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Solution Overview
Problem
The development of all-solid-state batteries requires a lithium ion conductor that can freely adjust ionic conductivity to minimize ion conductivity loss during manufacturing, particularly in stacked batteries, while maintaining stability and performance.
Innovation Solution
A lithium ion conductor composed of lithium (Li), silicon (Si), and boron (B) oxides with controlled crystallinity and porosity, specifically formulated to include 45-80 mol% Li2O, 5-20 mol% SiO2, and 15-50 mol% B2O3, and optionally additional oxides, is used, with a method involving firing oxide powders under pressure to achieve a crystallinity of ≤25.5% and porosity ≤1%, ensuring stable ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If high-temperature sintering process is used to manufacture oxide all-solid-state battery, then stability is improved, but ion conductivity decreases
Solution Approach 1:
The patent changes the sintering temperature parameter from conventional high temperatures (900-1100°C) to a lower temperature range (400-550°C), which prevents excessive crystallization and maintains amorphous structure with controlled crystallinity (≤25.5%). This parameter change resolves the contradiction by achieving both stability through controlled crystallization and high ion conductivity through maintained amorphous content
Solution Approach 2:
The patent creates a composite structure within the oxide electrolyte by controlling the coexistence of amorphous and crystalline phases. The amorphous phase provides high ion conductivity while the crystalline phase provides structural stability. This composite approach at the microstructural level resolves the contradiction between stability and ion conductivity
2Stability of the object's composition
If crystallinity is increased to improve structural stability, then stability is improved, but ion conductivity decreases
Solution Approach 1:
The patent establishes a specific parameter range for crystallinity (≤25.5%) that optimizes the balance between structural stability and ion conductivity. By controlling crystallinity within this range through controlled sintering, the patent achieves both desired properties simultaneously
Solution Approach 2:
The patent maintains a continuous amorphous matrix structure that provides continuous ion conduction pathways. By limiting crystallinity to ≤25.5%, the amorphous phase remains continuous and interconnected, ensuring uninterrupted ion transport while providing sufficient structural stability
3Ease of manufacture
If porosity is increased to reduce manufacturing stress, then ease of manufacture is improved, but ion conductivity decreases
Solution Approach 1:
The patent optimizes the porosity parameter to a specific range (0.1-5%) that balances manufacturing ease with ion conductivity. This controlled porosity level reduces manufacturing stress while maintaining sufficient ion conduction pathways through the electrolyte structure
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for predictable and maintained ion conductivity in stacked all-solid-state batteries, enhancing their performance and stability by controlling crystallinity and porosity, thus overcoming the challenges of ion conductivity loss during manufacturing.
Implementation Method 1
a solid electrolyte layer including a lithium ion conductor having a crystallinity of 25.5% or less
Implementation Method 2
firing oxide powders including lithium (Li), silicon (Si), and boron (B) while pressurizing
Data Source
AI summary
A lithium ion conductor for an all-solid-state battery according to present disclosure includes an oxide including lithium (Li), silicon (Si), and boron (B) and has a crystallinity of less than or equal to 25.5%.